A really stupid question about the repeating stopwatch in GWX 2.0

[Mush Martin]

If you mean change to the next torpedo to see when its due to hit.
then Its click on the torpedo icons at the top left

if you mean button click start and stop just click on the stopwatch
button itself on the image where you would a real stopwatch

if you want to make it appear and dissappear I think its X .

MM